With the rapid aging of population, air pollution and smoking, patients of lung diseases and respiratory diseases are rapidly increasing. An oxygen delivery apparatus is widely used in respiratory assistance for the patients of lung diseases and respiratory diseases in breathing. In particular, oxygen therapy is almost the only effective way for treatment of chronic obstructive pulmonary disease (COPD).
The oxygen therapy means a treatment for preventing saturation of oxygen in blood from being lowered by facilitating an increase in the fraction of inspired oxygen (FIO2) in lung by delivering oxygen of a higher concentration than atmospheric oxygen to patients of lung diseases. In the conventional oxygen therapy, a continuous flow oxygen (CFO) method and a demand oxygen delivery (DOD) method are used.
In the CFO method, a constant amount of oxygen is continuously supplied to a patient. According to the CFO method, since oxygen delivery is performed even when oxygen is not required by the patient, the oxygen may be considerably squandered. In the DOD method, a high flow oxygen stream is supplied to a patient for a short time by sensing a patient's inhale time. According to the DOD method, a considerable oxygen saving effect can be achieved. However, the patient may feel uncomfortable due to abruptly induced oxygen, making it difficult to employ the DOD method for a long time or in patient's sleep.